The invention relates to a cross-country or touring ski binding with a mechanism for attaching an associated boot so that the boot can be swivelled about an axis in its front region that extends approximately parallel to the boot sole and approximately perpendicular to the long direction of the sole and ski, and with a device for elastically returning the boot from a tilted-upward position into a position approximately parallel to the ski.
Cross-country or touring ski bindings of this kind are generally known, for example from European Patent No. 424 479 and U.S. Pat. No. 5,190,310. This sort of cross-country or touring ski binding is characterized by an elastic restoring element or so-called xe2x80x9cflexor,xe2x80x9d which is disposed between the front end of the ski-boot sole, in particular the front edge of the sole, and a binding case. Then lifting of the heel of the boot is opposed by the elastic action of the said flexor.
Another kind of cross-country or touring ski binding is characterized in that the elastic restoring element has the form of an elastic traction element that acts behind the swivelling axis of the boot, in the ball region of the sole, and tends to pull the boot back into a position parallel to the ski when the heel is raised. The pulling action of this element can be brought about by the force exerted by either an extension spring or a compression spring. A construction of this kind is described, for example, in European Patent No. 768 103.
Both kinds of bindings are thus characterized by only one elastic restoring element or a single flexor, against the action of which the heel of the boot can be raised. A disadvantage of this basic principle of construction is that at the beginning of the process of raising the heel it is only slightly effective if at all, with the consequence that the front part of the ski, in particular the upwardly curved tip (the shovel), stays on the ground so that it is not yet possible to initiate a change of direction with the ski. The danger of falling over the ski shovel would be too great. This disadvantage becomes particularly noticeable during racing.
The object of the present invention is thus to create a binding system that can be counterbalanced in such a way that when the boot is raised and hence its heel swung up, this movement is initially reinforced, so that the ski with its shovel is separated from the ground, with the result that the ski can be used to initiate a change of direction with no danger of falling.
This object is achieved in accordance with the invention by an additional elastically deformable element that counteracts the operation of the device for elastic restoration of the boot""s position, in particular when the boot is first being tilted up. That is, two elastic restoring elements are acting on the boot, one of which promotes tilting upwards while the other counteracts such tilting. Accordingly, the elastic restoring elements act on the two sides of the boot""s axis of rotation, in opposite directions. The strength of the elastic restoring force can be made different in different elements. Preferably it can be varied by adjustment. To permit variation the elastic restoring elements can be so constructed as to be exchangeable by simple means. In principle a construction is also conceivable that would allow the hardness of the elastic restoring elements to be continuously finely adjustable, for instance by integration of a helical compression spring, the tension of which can be made more or less strong by turning an adjustment screw.
Many cross-country or touring ski bindings are characterized in that the mechanism by which the boot is coupled at the front part of the sole, in particular at its front end, to engagement elements of the binding comprises insertable, complementary engagement elements to produce a joint-like connection, such that the sole-sided engagement elements consist of an axle oriented transverse to the long direction of the ski and about parallel to the sole, and the complementary engagement elements on the binding side comprise a retaining element that extends over or under the joint axle so as to form therewith a swivel bearing or hinge joint, and that can be moved out of a closed position into a release position by means of a handle disposed on the binding, in particular an actuating lever. In addition there is provided either an elastically deformable pressure element or flexor that acts between the boot and the binding or the ski in the region in front of the joint axle, in particular at the front end of the sole, or an elastically deformable traction element that acts between the boot and the binding or the ski in the region behind the joint axis, in particular the ball region of the sole, the action in either case tending to move the boot back towards the ski when its heel has been raised from the upper surface of the ski. In order to counteract the elastically deformable restoring element or flexor in such a binding, in accordance with the invention there is provided a separate elastically deformable element, either in the form of an elastically deformable pressure element or flexor disposed behind the joint axle, i.e. in the ball region of the front sole of the boot, or in the form of an elastically deformable traction element attached ahead of the joint axle.
The restoring force of the elastically deformable restoring element or flexor ordinarily increases progressively as the boot heel is raised. Preferably the force exerted by the element provided to elastically counteract this restoring element decreases uniformly. This means that the element counteracting the elastic restoring element or flexor initially acts more strongly, as a result of which the effect cited above is particularly well achieved.
The principle in accordance with the invention can also be applied in the case of a binding such that the boot is held on a boot-holding element mounted so that it can swing about an axis that extends approximately parallel to the tread of the sole and approximately transverse to the long direction of the ski, in particular on a pivotably mounted plate. In this case the element that counteracts the elastic restoring force exerted on the boot acts on the pivotably mounted boot-holding element or the pivotably mounted plate.